Appendix 1.

Performance on individual neuropsychological tests

		Young		Middle-age		Old		Age Effects within each Cognitive Group	Overall Age Effect	Overall Cognitive Status Effect	Age by Cognitive Status Interaction
		Mean	SD	Mean	SD	Mean	SD	p-value	p-value	p-value	p-value
Digit Span	Ave.	17.8	2.8	16.2	2.7	15.9	3.5	ns	ns	<.01	ns
	High	20.8	3.3	19.9	3.9	19.6	4.3	ns
Controlled Word Fluency (COWAT)	Ave.	41.7	9.9	38.9	10.0	29.8	9.9	<.01a,b	<.1	<.01	<.05
	High	45.9	14.4	51.8	13.0	48.4	10.8	ns
Boston Naming Test1	Ave.	54.3	2.2	55.7	3.3	54.9	3.3	ns	<.1c	<.01	ns
	High	56.5	1.9	58.3	2.5	56.9	3.3	ns
Category Generate (Animals)	Ave.	18.9	4.2	20.2	3.3	14.5	4.7	<.01d,e	<.01g,h	<.01	ns
	High	26.6	4.8	24.7	5.0	17.8	5.9	<.01d,f
WMS III Logical III Memory (Delayed Recall)2	Ave.	26.1	7.5	28.0	7.3	25.0	7.5	ns	<.1	<.01	ns
	High	34.1	6.7	32.7	6.3	28.8	3.9	<.05e
Benton Visual Retention Test (Correct)3	Ave.	7.7	1.3	7.0	1.2	6.3	1.1	<.01b	<.01i,j	<.01	ns
	High	9.0	0.9	8.6	0.9	6.9	1.3	<.01i,h

^aKey: p<.05 Old vs. Middle-aged,

^bp<.01 Old vs. Young,

^cp<.08 Middle-aged vs. Young,

^dp<.01 Old vs. Middle aged,

^ep<.05 Old vs. Young,

^fp<.01 Old vs. Young,

^gp<.01 Old vs. Middle-aged,

^hp<.01 Old vs. Young,

ⁱp<.01 Old vs. Middle-aged,

^jp<.01 Old vs. Young Maximum score:

¹60;

²50;

³10;

See text for information about each of the neuropsychological tests.